Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe the isolation and characterization of maize cDNAs that are transcribed from a small gene family and encode a novel group of receptor-like kinases (RLKs). The distinctive extracellular domain of these novel RLKs includes a unique number and arrangement of leucine-rich repeats (LRRs), a proline-rich region (PRR), a putative protein degradation target sequence (PEST), and a serine-rich region (SRR). The intracellular domain contains a putative serine/threonine protein kinase. To distinguish them from other reported RLKs, these novel RLKs were termed leucine-rich repeat transmembrane protein kinases (LTKs). Based on analysis of available deduced protein sequences, LTK1 and LTK2 were predicted to be 92.1% identical, while LTK2 and LTK3 were predicted to be 97.5% identical. Though the three LTK proteins showed high homology, the region that most distinguished LTK1 from LTK2 and LTK3 was found in the extracellular domain, in the SRR. To differentiate between expression of the individual ltk genes, we used the reverse transcriptase polymerase chain reaction (RT-PCR) in combination with restriction enzyme analysis. While ltk1 transcripts were constantly present in all tissues tested, ltk2 and ltk3 transcripts were only detected in the endosperm. Furthermore, transcript levels for both ltk1 and ltk2 showed modulation during endosperm development, peaking at 20 days after pollination. These results suggest that members of the ltk gene family mediate signals associated with seed development and maturation.
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PMID:The ltk gene family encodes novel receptor-like kinases with temporal expression in developing maize endosperm. 967 70

An abscisic acid (ABA)-induced cDNA fragment encoding a putative serine/threonine protein kinase (PK) was obtained by means of differential reverse transcriptase-polymerase chain reaction (RT-PCR). The full-length clone (FsPK4) was isolated from a cDNA library constructed using mRNA from ABA-treated Fagus sylvatica L. seeds. This clone contained the 11 catalytic domains present in all PKs and a highly acidic domain in the C-terminus. By expressing FsPK4 in Escherichia coli as a His tag fusion protein, we obtained direct biochemical evidence supporting Ca2+-dependent kinase activity of this protein. The expression of FsPK4 increased after ABA treatment or warm pre-treatment, when seeds are maintained dormant, but decreased and tended to disappear when dormancy was released by stratification or under gibberellic acid (GA3) treatment, and when seeds were artificially dried. Further, FsPK4 transcript expression is tissue specific, and was found to accumulate in ABA-treated seeds rather than in other ABA-treated vegetative tissues examined. These results suggest that the expression of the corresponding protein could be more closely related with the maintenance of seed dormancy than with responses to drought stress mediated by ABA.
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PMID:Characterization of a protein kinase (FsPK4) with an acidic domain, regulated by abscisic acid and specifically located in Fagus sylvatica L. seeds. 1661 87